Washing machine detecting condensed water temperature and drying control method of the same

ABSTRACT

Disclosed herein are a washing machine with a drying unit and a drying control method of the same that is capable of controlling a drying time based on a temperature of condensed water used during a drying operation to accomplish optimum drying efficiency. The drying control method includes detecting the temperature of condensed water supplied during drying the laundry, setting the drying time based on the detected temperature of the condensed water, and operating the drying unit according to the set drying time to perform a drying operation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2007-22211, filed on Mar. 6, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to a washing machine with a drying unit, and, more particularly, to a washing machine and a drying control method of the same that is capable of detecting a temperature of condensed water used during a drying operation to control drying time.

2. Description of the Related Art

Generally, a drying unit is a unit to supply hot air heated by a heater into a drum, while the drum, in which wetted clothes (laundry) are received, is rotated at a low speed such that the clothes are dried by the hot air. Recently, there has been marketed a washing-and-drying machine (normally, a drum-type washing machine) including a drying unit that is capable of performing only a drying operation or performing a drying operation after the completion of spin-drying in connection with a washing operation.

A washing machine with such a drying unit is disclosed in Korean Registered Patent Publication No. 10-0435241. The disclosed washing machine is constructed in a structure in which, after the completion of a spin-drying operation, high-temperature dry air (hot air) generated by a heater and a fan is introduced into a drum to remove moisture contained in laundry, which is changed into high-temperature, high-humidity air, and is transferred to a condensing duct. Then, a condensing process is carried out to remove the moisture taken from laundry from the air. To this end, the high-temperature, high-humidity air is brought into contact with cool water (condensed water) with the result that the high-temperature, high-humidity air is condensed and thus changed into dry air. The dry air is reheated by the heater, and the reheated air is introduced into the drum. The above procedure is repeated to dry the laundry.

The condensed water used during the condensing process is tap water (cool water) for domestic use, the temperature of which is changed due to seasonal or other environmental causes. For example, the tap water has a temperature distribution including the highest temperature of 30° in summer and the lowest temperature of 5° in winter. In foreign countries, especially some Middle Eastern areas, the temperature of tap water often exceeds 45°. In this case, when the temperature of the condensed water is low, the condensing efficiency is high with the result that the drying efficiency is increased. However, when the temperature of the condensed water is high, the condensing efficiency is low with the result that the drying efficiency is decreased.

An algorithm (specifically, for drying time), used during the drying process of the conventional washing machine with the drying unit, is equally applied irrespective of the difference in temperature of the condensed water. As a result, the drying efficiency is lowered depending upon the temperature of the condensed water, which is a cause of consumers' dissatisfaction.

Specifically, when the temperature of the condensed water is low, the drying process is continuously carried out for the remaining drying time, due to the low temperature of the condensed water, although the clothes are sufficiently dried. As a result, the clothes are damaged due to the overdryness, and in addition, the washing machine is badly affected due to the overheating of the washing machine. On the other hand, when the temperature of the condensed water is high, the drying process is completed after the elapse of the predetermined drying time, due to the high temperature of the condensed water, the drying time is insufficient. As a result, the clothes are not sufficiently dried, resulting in consumers' dissatisfaction.

SUMMARY

Therefore, it is an aspect of the embodiment to provide a washing machine with a drying unit and a drying control method of the same that is capable of controlling drying time based on the temperature of condensed water used during a drying operation to accomplish optimum drying efficiency.

Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

The foregoing and/or other aspects are achieved by providing a drying control method of a washing machine with a drying unit to dry laundry, the drying control method including detecting a temperature of condensed water supplied during the drying of the laundry, setting a drying time based on the detected temperature of the condensed water, and operating the drying unit according to the set drying time to perform a drying operation.

The detecting the temperature of the condensed water includes detecting the temperature of cool water supplied to remove moisture contained in the laundry.

The setting the drying time includes setting the drying time such that the drying time is decreased when the detected temperature of the condensed water is low, and the drying time is increased when the detected temperature of the condensed water is high.

The setting the drying time includes detecting a weight of laundry to be dried, searching the drying time of a plurality of drying times corresponding to the detected weight of the laundry, and adjusting the searched drying time based on the detected temperature of the condensed water to set the set drying time.

The adjusting the drying time is decreasing the drying time when the temperature of the condensed water is lower than a reference temperature range, and increasing the drying time when the temperature of the condensed water is higher than the reference temperature range.

The reference temperature range may be approximately 15.1 to 25°.

The foregoing and/or other aspects are achieved by providing a washing machine including a rotary drum receiving laundry to be dried, a drying unit supplying hot air into the rotary drum such that the laundry is dried, a duct guiding the hot air to the rotary drum, a valve controlling a supply of condensed water during drying of the laundry, a temperature sensor detecting a temperature of the condensed water supplied, and a control unit controlling the valve to supply the condensed water to the duct, setting a drying time based on the temperature of the condensed water detected by the temperature sensor, and operating the drying unit according to the set drying time to perform a drying operation.

The drying unit may include a heater generating hot air and a fan supplying the hot air into the rotary drum.

The hot air, supplied into the rotary drum is changed into high-temperature, high-humidity air due to moisture contained in the laundry, and the high-temperature, high-humidity air is guided to the drying unit through the duct.

The temperature sensor may detect the temperature of cool water supplied to the duct to remove moisture contained in the laundry.

The control unit may set the drying time such that the drying time is decreased when the detected temperature of the condensed water is low, and the drying time is increased when the temperature of the condensed water is high.

The control unit may detect a weight of laundry to be dried and adjust the drying time searched according to the detected weight of the laundry based on the temperature of the condensed water.

The control unit may compare the temperature of the condensed water with a predetermined reference temperature range and decrease the drying time when the temperature of the condensed water is lower than the reference temperature range, and increases the drying time when the temperature of the condensed water is higher than the reference temperature range.

The foregoing and/or other aspects are achieved by providing a method of controlling a washing machine including a condensing duct, including: detecting a weight of laundry to be dried; determining a drying time to perform a drying operation based on the detected weight of the laundry; detecting a temperature of water supplied to the condensing duct; and increasing, decreasing or maintaining the determined drying time based on the detected temperature.

The foregoing and/or other aspects are achieved by providing a method of controlling a washing machine including a condensing duct, including: detecting a weight of laundry to be dried; detecting a temperature of water supplied to the condensing duct; and setting a drying time to perform a drying operation of the laundry based on the detected weight of the laundry and the detected temperature of the water.

The foregoing and/or other aspects are achieved by providing a washing machine, including: a drying unit supplying hot air to laundry to be dried; a condensing duct introducing air to the drying unit; a temperature sensor detecting a temperature of water supplied to the condensing unit; and a control unit detecting a weight of the laundry, selecting a drying time from a plurality of stored drying times based on the detected temperature of the condensed water and the detected weight of the laundry, and operating the drying unit according to the selected drying time to perform a drying operation.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:

FIG. 1 is a sectional view illustrating the structure of a washing machine with a drying unit according to the present embodiment;

FIG. 2 is a control block diagram of the washing machine with the drying unit according to the present embodiment;

FIG. 3 is a flow chart illustrating a drying control method of the washing machine with the drying unit according to the present embodiment;

FIG. 4 is a table showing drying time based on the weight of laundry to be dried according to the present embodiment;

FIG. 5 is a table showing adjustment of drying time based on the temperature of condensed water according to the present embodiment; and

FIG. 6 is an experimental data table showing dryness and drying time based on the temperature of condensed water according to the present embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENT

Reference will now be made in detail to the embodiment, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the figures.

FIG. 1 is a sectional view illustrating the structure of a washing machine with a drying unit according to the present embodiment.

Referring to FIG. 1, the washing machine includes a drum-type water tub 11 mounted in a machine body 10 to receive water (wash water or rinse water) and a rotary drum 12 rotatably mounted in the water tub 11. The rotary drum 12 has a plurality of spin-drying holes.

Below the water tub 11 is mounted a motor 13 to rotate the rotary drum 12 in alternating directions such that washing, rinsing, and spin-drying operations are performed. At an inside bottom of the water tub 11 is mounted a washing heater 16 to heat water (specifically, wash water) supplied into the water tub 11 according to a user's selection of a temperature of water.

In the front of the water tub 11 and the rotary drum 12 is formed an opening 14, through which a user withdraws clothes in front of the machine body 10. At the front of the machine body 10 is mounted a door 15 to open and close the opening 14.

Above the water tub 11 are mounted a detergent supply unit 18 to supply detergent and a water supply unit 20 to supply water (wash water or rinse water).

The detergent supply unit 18 has several partitioned spaces. The detergent supply unit 18 is mounted at a front side of the machine body 10 such that a user may easily put detergent and rinse into the respective partitioned spaces.

The water supply unit 20 includes a water supply pipe 22 to supply water and a water supply valve 24 mounted on the water supply pipe 22 to control the supply of water. The water supply pipe 22 is connected to the detergent supply unit 18 such that water from the outside is supplied to the detergent supply unit 18. Between the detergent supply unit 18 and the water tub 11 is mounted a connection pipe 26, through which the water having passed through the detergent supply unit 18 is supplied into the water tub 11 together with detergent. At the inlet of the connection pipe 26 is mounted a water supply nozzle 28. Consequently, the detergent in the detergent supply unit 18 is supplied into the water tub 11 while being dissolved in the water.

The washing machine further includes a drainage unit 30 to drain the water in the water tub 11. The drainage unit 30 includes a drainage pipe 31 connected to a bottom of the water tub 11 to guide the water in the water tub 11 to the outside and a drainage pump 32 mounted on the drainage pipe 31.

The washing machine further includes a drying unit 40 to dry laundry (clothes). The drying unit 40 includes a drying fan 41 above the water tub 11, a drying duct 42 connected between an outlet port 41 b of the drying fan 41 and an air introduction port 45 formed in an upper side of the opening 14 of the water tub 11, a condensing duct 43 mounted at a rear of the water tub 11 such that the condensing duct 43 is connected between an air discharge port 46 formed in the rear bottom of the water tub 11 and an inlet port 41 a of the drying fan 41, and a drying heater 44 mounted in the drying duct 42 to generate high-temperature air, which is supplied into the rotary drum 12.

In the upper part of the condensing duct 43 is mounted an injection nozzle 47 to inject condensed water (cool water) into the condensing duct 43 such that moisture is condensed and removed during the passage of high-temperature, high-humidity air, generated by drying the laundry, along the condensing duct 43.

The injection nozzle 47 is connected to the water supply unit 20, via a condensed water supply pipe 48 and a condensed water valve 49, such that condensed water is supplied to the injection nozzle 47.

Consequently, the condensed water, injected from the injection nozzle 47, flows to a lower part of the condensing duct 43 along an inner surface of the condensing duct 43. As a result, the contact between the condensed water and high-temperature, high-humidity air rising from the lower part of the condensing duct 43 is increased, and therefore the condensing efficiency is improved.

In the lower part of the condensing duct 43 is formed a discharge port 43 a through which the condensed water is discharged, such that the condensed water that is discharged through the discharge port 43 a, is introduced into the drainage pipe 31 of the drainage unit 30. In the lower part of the condensing duct 43, adjacent to the discharge port 43 a, is mounted a temperature sensor 50 to detect the temperature of the condensed water injected into the condensing duct 43.

The temperature sensor 50 controls drying time differently depending upon the temperature of the condensed water to accomplish optimum drying efficiency irrespective of the difference in temperature of the condensed water injected during the condensing process. For example, when the temperature of the condensed water is low, the drying time is decreased in consideration of a fact that when the temperature of the condensed water is low, the condensing efficiency is increased, and thus the drying efficiency is increased. On the other hand, when the temperature of the condensed water is high, the drying time is increased in consideration of a fact that when the temperature of the condensed water is high, the condensing efficiency is decreased, and thus the drying efficiency is decreased.

The washing machine with the drying unit is operated as follows.

When a user puts laundry in the rotary drum 12 and operates the washing machine, the water supply valve 24 of the water supply unit 20 is opened with the result that water (wash water) is supplied into the water tub 11 via the water supply pipe 22 and the detergent supply unit 18.

After the completion of water supply, the washing heater 16 is operated to heat the wash water in the water tub 11 to a temperature necessary to wash the clothing. The rotary drum 12 is rotated in alternating directions by the motor 13. As a result, the laundry is washed by the frictional force between the laundry and the rotary drum and a dissolving force of the detergent.

After the completion of the washing, a rinsing operation based on a repetition of spin-drying and the water supply, and a spin-drying operation based on the high-speed rotation of the rotary drum 12 are performed.

Subsequently, a drying operation is performed. When the drying heater 44 and the drying fan 41 are operated, during the drying operation, while the rotary drum 12 is rotated slowly by the motor 13, air in the rotary drum 12 is introduced to the drying fan 41 through the condensing duct 43, and is discharged into the rotary drum 12 through the drying duct 42. This circulation of the air is repeated.

At this time, the air in the drying duct 42 is heated by the drying heater 44. The high-temperature dry air is introduced into the rotary drum 12, and the laundry in the rotary drum 12 is heated by the high-temperature dry air (hot air) with the result that moisture contained in the laundry is evaporated, and therefore the laundry is dried.

During the drying operation, the high-temperature dry air absorbs the moisture from the wet laundry, and therefore, the high-temperature dry air is changed into high-temperature, high-humidity air. The high-temperature, high-humidity air is transferred to the condensing duct 43, where the high-temperature, high-humidity air is brought into contact with condensed air (cool air) injected through the injection nozzle 47. As a result, the high-temperature, high-humidity air is condensed and thus changed into dry air. The dry air is reheated by the drying heater 44 and introduced into the rotary drum. The above procedure is repeated to dry the laundry.

FIG. 2 is a control block diagram of the washing machine with the drying unit according to the present embodiment. In addition to the components shown in FIG. 1, the washing machine further includes a signal input unit 100, a water level detection unit 110, a dryness detection unit 120, a control unit 130, and a drive unit 140.

The signal input unit 100 inputs operation information, such as a washing course, a washing temperature, spin-drying RPM, and the addition of rinsing, which are selected by a user, to the control unit 130. Specifically, the signal input unit 100 selects and inputs a single drying course to perform only a drying operation or a post-operation drying course to perform a drying operation after the completion of spin-drying in connection with a washing operation to the control unit 130.

The water level detection unit 110 detects the water level of water supplied into the water tub 11, and the dryness detection unit 120 detects the temperature and humidity of the laundry to confirm the dryness of the laundry.

The control unit 130 is a microcomputer, for example, to control the washing machine based on the operation information inputted from the signal input unit 100. When the single drying course or the post-operation drying course is selected, the control unit 130 controls the drying unit 40 to dry the laundry. Specifically, the control unit 130 controls differently the drying time based on the temperature of condensed water injected during the drying operation.

The drive unit 140 drives the motor 13, the washing heater 16, the water supply valve 24, the drainage pump 32, the drying fan 41, the drying heater 44, and the condensed water valve 49 according to a drive control signal of the control unit 130.

Hereinafter, the operation of the washing machine with the above-stated construction and a drying control method of the washing machine will be described.

FIG. 3 is a flow chart illustrating a drying control method of the washing machine with the drying unit according to the present embodiment. The drying control method according to the present embodiment is applicable to any courses to perform a drying operation, including a single drying course to perform only a drying operation and a post-operation continuous drying course to perform a drying operation after the completion of spin-drying in connection with a washing operation.

When a user selects a single drying course or a post-operation continuous drying course to dry wet laundry (clothes) received in the rotary drum 12, the operation information selected by the user is inputted to the control unit 130 through the signal input unit 100.

Subsequently, the control unit 130 determines whether the selected operation is a drying operation based on the operation information inputted from the signal input unit 100 (200).

When the selected operation is the drying operation, the control unit 130 controls the condensed water valve 49 to supply condensed water (cool water) necessary to dry the laundry. As a result, normal tap water (cool water) is supplied to the injection nozzle 47 through the condensed water supply pipe 48 and is injected into the condensing duct 43 through the injection nozzle 47 (202). If the selected operation is not the drying operation, the procedure returns to operation 200.

Then, the temperature of the condensed water injected into the condensing duct 43 is detected by the temperature sensor mounted in the condensing duct 43, and the detected temperature is inputted to the control unit 130 (204).

The condensed water injected into the condensing duct 43 is tap water (cool water) for domestic use. The temperature of the tap water may be changed due to seasonal or other environmental causes. For example, the tap water has a temperature distribution including a highest temperature of 30° in summer and a lowest temperature of 5° in winter. In foreign countries, especially some Middle Eastern areas, the temperature of tap water often exceeds

Subsequently, the control unit 130 detects the weight of laundry (clothes) to be dried (206), and searches for a drying time corresponding to the detected weight of the laundry using a table showing drying time based on the weight of laundry to be dried as shown in FIG. 4 (208).

FIG. 4 is a table showing drying times based on the weight of laundry to be dried. For example, when the weight of laundry to be dried is 2 to 3 kg, the drying time is set to be 90 minutes. When the weight of laundry to be dried is 3 to 5 kg, the drying time is set to be 120 minutes.

Subsequently, the control unit 130 adjusts the drying time corresponding to the detected temperature of the condensed water by adding or subtracting the drying time searched from FIG. 4 using a table showing an adjustment of drying times based on the temperature of condensed water as shown in FIG. 4 (210).

The addition and subtraction of the drying time are accomplished by decreasing the drying time when the temperature of the condensed water is lower than a predetermined temperature range (approximately 15.1 to 25°), and increasing the drying time when the temperature of the condensed water is higher than the predetermined temperature range.

FIG. 5 is a table showing an adjustment of a drying time based on the temperature of condensed water when the weight of laundry to be dried is 3 kg. For example, when the temperature of the condensed water is 0 to 15°, the drying time is subtracted by 5 minutes. When the temperature of the condensed water is 25.1 to 35°, the drying time is added by 10 minutes.

This is to adjust the drying time based on the temperature of condensed water in consideration of a fact that the drying efficiency is increased when the temperature of the condensed water is low, and the drying efficiency is decreased when the temperature of the condensed water is high.

Consequently, the control unit 130 controls the motor 13 to slowly rotate the rotary drum 12 such that the laundry is dried during the drying time that is adjusted based on the temperature of the condensed water. At this time, the drying heater 44 and the drying fan 41 are operated such that air in the rotary drum 12 is introduced to the drying fan 41 through the condensing duct 43, and is discharged into the rotary drum 12 through the drying duct 42. This circulation of the air is repeated.

At this time, the air in the drying duct 42 is heated by the drying heater 44. The high-temperature dry air is introduced into the rotary drum 12, and the laundry in the rotary drum 12 is heated by the high-temperature dry air (hot air) with the result that moisture contained in the laundry is evaporated, and therefore, the laundry is dried.

During the drying operation, the high-temperature dry air absorbs the moisture from the wet laundry, and therefore, the high-temperature dry air is changed into high-temperature, high-humidity air. The high-temperature, high-humidity air is transferred to the condensing duct 43, where the high-temperature, high-humidity air is brought into contact with condensed air (cool air) injected through the injection nozzle 47. As a result, the high-temperature, high-humidity air is condensed and thus changed into dry air. The dry air is reheated by the drying heater 44 and introduced into the rotary drum. The above procedure is repeated to dry the laundry (212).

FIG. 6 is an experimental data table showing dryness and drying time changed depending upon the temperature of condensed water when the weight of laundry to be dried is 2957.6 g (approximately 3 kg). It can be seen from FIG. 6 that the dryness is lowered and the drying time is increased with the increase of the temperature of the condensed water.

Turning back to FIG. 3, the control unit 130 counts the drying time, during the drying operation, to determine whether a predetermined drying time has elapsed (214). When the predetermined drying time has not elapsed, the procedure returns to 212 to continuously perform the drying operation.

When it is determined at 214 that the predetermined drying time has elapsed, the control unit 130 stops the drying heater 44, the drying fan 41, and the motor 13 to interrupt the drying operation (216).

As apparent from the above description, the washing machine with the drying unit according to the present embodiment and the drying control method of the same have the effect of controlling drying time based on the temperature of condensed water used during the drying operation to accomplish optimum drying efficiency, thereby increasing consumers' satisfaction.

Although an embodiment has been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A drying control method of a washing machine with a drying unit to dry laundry, the drying control method comprising: detecting a temperature of condensed water supplied during the drying of the laundry; setting a drying time based on the detected temperature of the condensed water; and operating the drying unit according to the set drying time to perform a drying operation.
 2. The drying control method according to claim 1, wherein the detecting the temperature of the condensed water includes detecting the temperature of cool water supplied to remove moisture contained in the laundry.
 3. The drying control method according to claim 1, wherein the step of setting the drying time includes: setting the drying time such that the drying time is decreased when the detected temperature of the condensed water is low, and the drying time is increased when the detected temperature of the condensed water is high.
 4. The drying control method according to claim 1, the setting the drying time comprising: detecting a weight of laundry to be dried; searching the drying time of a plurality of drying times corresponding to the detected weight of the laundry; and adjusting the searched drying time based on the detected temperature of the condensed water to set the set drying time.
 5. The drying control method according to claim 4, wherein the adjusting the drying time is decreasing the drying time when the temperature of the condensed water is lower than a reference temperature range, and increasing the drying time when the temperature of the condensed water is higher than the reference temperature range.
 6. The drying control method according to claim 5, wherein the reference temperature range is approximately 15.1 to 25°.
 7. A washing machine, comprising: a rotary drum receiving laundry to be dried; a drying unit supplying hot air into the rotary drum such that the laundry is dried; a duct guiding the hot air to the rotary drum; a valve controlling a supply of condensed water during drying of the laundry; a temperature sensor detecting a temperature of the condensed water supplied; and a control unit controlling the valve to supply the condensed water to the duct, setting a drying time based on the temperature of the condensed water detected by the temperature sensor, and operating the drying unit according to the set drying time to perform a drying operation.
 8. The washing machine according to claim 7, wherein the drying unit includes a heater generating hot air and a fan supplying the hot air into the rotary drum.
 9. The washing machine according to claim 7, wherein the hot air supplied into the rotary drum is changed into high-temperature, high-humidity air due to moisture contained in the laundry, and the high-temperature, high-humidity air is guided to the drying unit through the duct.
 10. The washing machine according to claim 7, wherein the temperature sensor detects the temperature of cool water supplied to the duct to remove moisture contained in the laundry.
 11. The washing machine according to claim 7, wherein the control unit sets the drying time such that the drying time is decreased when the detected temperature of the condensed water is low, and the drying time is increased when the temperature of the condensed water is high.
 12. The washing machine according to claim 7, wherein the control unit detects a weight of laundry to be dried and adjusts the drying time searched according to the detected weight of the laundry based on the temperature of the condensed water.
 13. The washing machine according to claim 12, wherein the control unit compares the temperature of the condensed water with a predetermined reference temperature range and decreases the drying time when the temperature of the condensed water is lower than the reference temperature range, and increases the drying time when the temperature of the condensed water is higher than the reference temperature range.
 14. The washing machine according to claim 13, wherein the reference temperature range is approximately 15.1 to 25°.
 15. A method of controlling a washing machine including a condensing duct, comprising: detecting a weight of laundry to be dried; determining a drying time to perform a drying operation based on the detected weight of the laundry; detecting a temperature of water supplied to the condensing duct; and increasing, decreasing or maintaining the determined drying time based on the detected temperature.
 16. A method of controlling a washing machine including a condensing duct, comprising: detecting a weight of laundry to be dried; detecting a temperature of water supplied to the condensing duct; and setting a drying time to perform a drying operation of the laundry based on the detected weight of the laundry and the detected temperature of the water.
 17. A washing machine, comprising: a drying unit supplying hot air to laundry to be dried; a condensing duct introducing air to the drying unit; a temperature sensor detecting a temperature of water supplied to the condensing unit; and a control unit detecting a weight of the laundry, selecting a drying time from a plurality of stored drying times based on the detected temperature of the condensed water and the detected weight of the laundry, and operating the drying unit according to the selected drying time to perform a drying operation. 